The invention relates to a zoom lens and a photographing apparatus.
Focusing mechanisms of zoom lenses at a minimum distance are classified into focusing by a first lens group that is closest to an object side and focusing by a lens group other than the first lens group.
A zoom lens focused by the first lens group can be easily designed due to its simple structure. In particular, in a zoom lens including a positive lens having a wide angle region which is disposed at the front of the first lens group, the diameter of the zoom lens may be increased. A zoom lens focused by a lens group other than the first lens group which overcomes drawbacks of the zoom lens focused by the first lens group is focused by a negative second lens group disposed at an image side of the first lens group and includes a positive lens disposed at the front of the second lens group, and thus is suitable for high zoom magnification.
However, in the zoom lens in which the focusing is performed by the negative second lens group and the positive lens is disposed at the front of the negative second lens group, the second lens group generally plays a critical role in zooming, and thus the number of lenses may increase and the weight of the zoom lens may also increase. Thus, such a zoom lens is not suitable for controlling a minute shift of the second lens group forward or backward, in particular, auto-focusing control by bokeh sensing of an imaging device.
It is also known that, a zoom lens including a positive first lens group, a negative second lens group, and a positive third lens group which are sequentially arranged from an object side may be focused by the third lens group.
However, since the number of lenses increases when the focusing is performed by the third lens group, a minute control of the third lens group, for example a minute shift of the third lens group forward or backward, is not easy.